It is known to use directed beams of particles, including but not limited to protons, heavier ions (such as carbon), and mesons, to attack and destroy cancer cells. Particle therapy has an advantage over traditional radiation therapy in that the particle beam can be directed to a particular depth within a patient's body; because, unlike an x-ray beam, the particle beam deposits little energy in the tissue through which it passes, but deposits a large amount of energy at its end point, the beam can kill cancer cells with minimal damage to intervening tissue. Dose to the tissue surrounding the tumor is further reduced by arranging for the beam to reach the tumor from many different directions, such as over an arc of up to 360 degrees. Conventional particle therapy involves generating a beam of fast-moving particles in a particle accelerator or a cyclotron. The beam is then directed along a desired path toward a patient. Because the beam must be delivered to the entire circumference of the target site, current systems direct the beam at the patient from a gantry rotating around the patient.
Conventional particle therapy devices place the patient in a horizontal position, and use magnets arranged in large gantry assemblies to direct the beam at the patient from locations around a 360-degree circumference. Because of the size of the particle beam generator, the magnets required to deflect the beam by a total of close to 180 degrees, and the gantry, this arrangement requires deep excavation at huge cost. Current systems incorporate gantries four or more meters in diameter, weighing over 90 tons. Further, the varying direction of the beam mandates that extensive radiation shielding is required around the entire circumference of the treatment area.
There is, therefore, a need for a particle therapy device and method that requires a smaller and less complicated structure.